Turn signal fuse blows. 72 gs

Hi guys. I have a 72 buick gs convertable. My turn signal fuse will blow at certain times. Will work for an hour or a few hours. When it blows i hear a buzzer. Sounds like the key ignition buzzer. But its another buzzer behind ashtray area. Had mechanic try and find it and keeps fuse keeps popping sparatickly. If anyone has any ideas. Love to hear them. Thank you


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LARRY70GS

Active member
That fuse also has back up lamps, cruise control, rear defogger, TCS solenoid, and power window relay. The wiring for any of that may have worn or broken insulation, or just be hanging there shorting to something when it moves.
 
That fuse also has back up lamps, cruise control, rear defogger, TCS solenoid, and power window relay. The wiring for any of that may have worn or broken insulation, or just be hanging there shorting to something when it moves.
Hi Larrry ty for info. Keep u posted


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Here is a re-post of my reply in the Conversations sections in case you didn't see it there. I have a tendency to pass over msgs posted there and sometimes lose track of items.
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Hi Brian, your fuse trouble is an interesting one to solve. Sorry it took so long to get back to you. I have been studying the shop manual off and on trying to develop a solution.

From the symptoms, something is causing a short circuit to ground on the load side of the 20 Amp Turn Signal/Backup Lights fuse. The buzzer that is sounding after the fuse blows is the Fasten Seat Belts buzzer. There is a sneak circuit in this model's design that feeds power to this buzzer as long as the short circuit is present. The Fasten Seat Belt warning light may glow dimly or not at all. The buzzer may sound weaker than normal operation as when a seat belt is left unbuckled. If the short goes away, the buzzer will stop.

Of course the Turn Signal fuse only gets power when the ignition switch is in Run or Start. So the fuse won't blow when the switch is Off.

The buzzer is not the problem causing the fuse to blow. It does act as a handy indicator that the short is present. Two major questions are: What is happening right before fuse blows and buzzer starts? What causes buzzer to stop (meaning the short goes away)? If the short is continuous, a new fuse would blow instantly every time one is inserted.

One easy answer (re: your recent transmission repairs) would be skinned or burned wiring going to the switches on the transmission if a 4-speed manual. Then the fuse might blow only when shifting into reverse for example. Shifting back to some other gear would clear the short.

There is a way to isolate some of the optional accessories mentioned in the Larry70GS reply that are fed by the Turn Signal fuse. There is a 1-pin ACC socket on the fuse block just to the left of the Turn Signal fuse. If anything is plugged in here like say a Cruise Control, it can be disconnected to see if it is causing the fuse to blow.

Water getting to the fuse block should not be able to blow the fuse -- only 12 volts present. The leaks should be fixed however to prevent other problems.
 
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